This invention related to an X-ray device and, although the invention is not so restricted, it more particularly relates to and X-ray device having an X-ray tube which is arranged to be corrected for any change in the intensity and/or wave height of the X-rays produced by the tube.
The conventional type, X-ray device as shown in FIG. 4, comprises an X-ray tube 1 and an X-ray detector 4 which has openings 5a, 5b for the transmission of X-rays thereto. The X-ray detector 4 is arranged to receive X-rays from the X-ray tube 1 by way of a guide passage 20 which communicates with the opening 5a, and the X-ray detector 4 is also arranged to receive fluorescent X-rays which are reflected from sample material 8, by way of the opening 5b. The X-ray tube 1 is provided with a shutter 21 which is movable between an open position, in which X-rays from the X-ray tube 1 may be directed onto the sample material 8 so that fluorescent X-rays may be reflected from the sample 8 and onto the X-ray detector 4, and a closed position in which the sample material 8 is prevented from receiving X-rays from the X-ray tube 1. The X-ray detector 4 is connected to a wave height discriminator 11, a scaler timer 12, and an automatic correction means 13 for correcting the X-rays produced by the X-ray tube 1 when the X-ray intensity and/or wave height change.
In the known construction shown in FIG. 4, corrected X-rays (i.e. X-rays whose intensity and/or wave height have been adjusted) are directed from the X-ray tube 1 onto the X-ray detector 4 while the shutter 21 is opened and the sample material 8 is receiving X-rays from the X-ray tube 1. However, there is an overlap between the spectrum of the X-rays from the X-ray tube 1 and the spectrum of the X-rays from the sample material 8 and this makes it difficult to effect an accurate measurement of certain properties of the sample material 8, e.g. the thickness of a layer thereon.
Generally, an X-ray correction is executed by measuring fluorescent X-rays irradiated from a sample after irradiating an X-rays on a correction sample. A certain measuring time for the fluorescent X-rays for exactly correcting the X-ray device is necessary.
Therefore, in an X-ray device in which X-ray correction is executed during the period that being a sample is not being measured, i.e., a shutter is kept in while the closed condition, measurement of a sample can not be executed until the fluorescent X-ray measurement for correction is finished.